Abstract: In spite of a well known fact that biological objects migrate up and down in a diurnal cycle according to the variable light conditions, there exist some detailed features characteristic for the specific areas. Vertical migrations were detected in different seasons at various points of the Baltic Sea, in Lake Wdzydze (Northern Poland) and in Lake Tanganyika (Africa). Those three areas are very different in size, water content and structure, biological life and meteorological conditions. Analysis of the vertical distribution of echoes and temporal dynamics of the aggregative behaviour is presented on the base of the spatial heterogeneity of abiotic environment.